If you go up to someone on the street and ask for classic comic arcs they’ll probably say “Infinity War and Endgame”

Comic-wise, there are some damn classic X-Men arcs, then Infinity (Gauntlet, War, Crusade) as well as Crisis on Infinite Earths and Judas Contract. Honestly, I’d say it’s pretty tied in comics

Very much this. And Iconic ends up being a mesh of most impactful plus most well-liked when those two are completely different. Fourth World is mentioned above as being iconic but it's more that it left a legacy that's spun into iconic characters and stories than iconic in a vacuum.

Most well known for casual readers - I'd say Marvel

Most Iconic runs - DC

Most iconic side verses(Vertigo, Watchman, V for Vendetta etc) - DC Destroys Marvel! BUT. You simply can't include these as part of the major DC zeitgistas when trying to cover a DC vs Marvel debate as most of the biggest stories were told away from what the general population think of as "DC." While nowhere near as good as most of the DC stuff, it would be like including 2099 or Ultimate comics in a conversation with people who only understand/are aware of 616.

Most Iconic/impactful Character arcs/stories - Toss-up but I'll go with Marvel. Practically everything that immediately jumps out is linked to the big Justice League characters (alone/team-ups) whereas Marvel has some astounding stuff covering street-level characters like Spider-Man, Daredevil, Moon Knight, to the entire Mutant side of the verse (tens of stories here), to the Avengers and their stuff (solo and together) to the cosmic like Infinity War and Annihilation, to the insane time-travel works.

Yeah, no. You don't get to *include* runs that haven't even finished yet.

Um, literally only onerun out of the handful I listed isn't finished yet, and it only has one issue left. I even clearly noted that it will ultimately depend on how well the final issue wraps up the run.

That being said, you're straining at a gnat here. Why not rather comment on the six other runs I mentioned that are finished instead of nitpicking over the one that isn't? Lol.

Incidentally, have you read the first two issues of Last Knight on Earth? I highly recommend. It's great stuff; shaping up to be an all-time iconic tale so long as the 3rd and final issue can even remotely stick the landing, which I believe it will.